Created
March 23, 2018 15:39
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<?php | |
class QueryMaker | |
{ | |
$table = ''; | |
$field = ''; | |
// this is a static method, it doesn't | |
// run on an object, it only runs on a class | |
public static function make() | |
{ | |
// create an instance of class | |
// QueryMaker and return it | |
return new static(); | |
} | |
// this is not static, it doesn't run on | |
// a class, only on an object | |
public function setTable($name) | |
{ | |
$this->table = $name; | |
return $this; | |
} | |
// this is also not static | |
public function setField($name) | |
{ | |
$this->field = $name; | |
return $this; | |
} | |
// again, not static, just renders | |
// the "query" | |
public function flush() | |
{ | |
return "select {$this->field} from {$this->table}"; | |
} | |
} | |
// Here is the implementation with method chaining | |
$query = QueryMaker::make()->setTable('users')->setField('name')->flush(); | |
// Here is the implementation without method chaining | |
$object = new QueryMaker(); | |
$object->setTable('users'); | |
$object->setField('name'); | |
$query = $object->flush(); | |
// the output is: select name from users | |
// The methods setTable() and setField() return $this. | |
// In that context $this is the QueryMaker object that was created by make(). | |
// Let's go step by step: | |
$query = QueryMaker::make()->setTable('users')->setField('name')->flush(); | |
// The static method QueryMaker::make() returns an object instantiation of the QueryMaker class. | |
$query = $object->setTable('users')->setField('name')->flush(); | |
// $object->table is set, setTable() returns the object instance. | |
$query = $object->setField('name')->flush(); | |
// $object->field is set, setField() returns the object instance. | |
$query = $object->flush(); | |
// The flush method is called on the object, returning the string. |
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